Aspects of Weather and Space Weather in the Earth's Upper Atmosphere The Role of Internal Atmospheric Waves (1997) / Chapter Skim
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Relationship of Internal Waves to Space Weather
Relationship of Internal Waves to Space Weather
Pages 22-29
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From page 22... ...
created havoc in Quebec and very nearly throughout the entire eastern seaboard of North America. Solar windmagnetospheric interactions are also responsible for the "killer electrons" that have wiped out numerous expensive communication satellites at geosynchronous orbit, and solar protons will make Mars missions and life aboard the space station dangerous indeed.
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From page 23... ...
This direction is the "path of least resistance" for internal waves since equatorward propagation also means that the bulk of the wave-induced plasma motion is parallel to the magnetic field lines, the near-frictionless direction. This can be understood as follows.
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From page 24... ...
FIGURE 22 Airglow emissions from the ionosphere make huge wavelike oscillations visible from the ground by using sensitive cameras. Reproduced from Mendillo et al.
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From page 25... ...
These waves were found not only to have the usual properties of gravity waves but to exhibit an electrical component as well (Kelley and Miller, 1997~. One wave packet studied simultaneously with the imager and the Arecibo radar had a nearly 1,000-volt potential across the wave fronts, giving rise to the term "electrobuoyancy wave." We know that steady winds and tides can create electrical potentials in the ionosphere by the dynamo effect, but the electric field measured in this particular wave was larger than this limit, and some examples have been reported that are an order of magnitude larger.
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From page 26... ...
~ I.,.,. ~ ~ ~ FIGURE 23 A space weather radar map provided by the Jicamarca Radio Observatory near Lima, Peru, shows that turbulence can be generated for hours over height ranges of hundreds of kilometers (Kelley et al., 1981~.
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From page 27... ...
This type of lazy undulation of the ionosphere creates the sort of smooth variations in total electron content discussed above in the GPS context and shown earlier in the Arecibo data and the all-sky images. Furthermore, they are now thought by many to provide the conditions needed to create the most severe weather in the Earth' s near-space environment: the towering plume structures characterizing equatorial spread F
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From page 28... ...
Thus, the initial undulation is made deeper by the electric field, and the lowdensity region grows upward, with the high density region pushed downward just like the hydrodynamic analogy. The gravity wave has stimulated an instability in the plasma, which quickly takes on a life of its own as if the initial wave did not even exist.
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From page 29... ...
These violent ionospheric storms have also been attributed to gravity wave seeding of the socalled Perkins instability in which energy is drawn from the background current system in the ionosphere. Much more work is needed to justify this claim, but the National Science Foundation program called CEDAR (Coupling Energetics and Dynamics of Atmospheric Response)
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